Accurate understanding of the characteristics of reservoir sedimentation is the material base for the petroleum reservoir evaluation. By means of the principle of high-resolution sequence stratigraphy, the sequence interface , lake flooded plane and the rise-and-drop cycles of the base level are recognized with the help of the properties stratigraphic petrology and geophysics. In Chaochang region of Songliao Basin, Quan No. 3 & 4 Members are divided into 1. 5 three-grade sequences corresponding three rise-and-drop cycles of the base level; and once more they are classified into 7 four-grade sequences corresponding fourteen rise-and-drop cycles of the base level. Finally the isochronal sequence stratigraphic framework is established and the problem of corresponding relation between the oil reservoir group and sequence formations is solved at last. On the basis of isochronal sequence classification, the typical sedimentary facies forms of meandering river, delta, lake and so on are determined; the material source from southwest direction is pointed out in the region. The reservoirs are mainly meandering river channel sandbodies distributed along NE strike and stacked during many periods.%准确认识储层沉积特征是油气藏评价的物质基础.应用高分辨率层序地层学原理,根据地层岩石学和地球物理学特征,识别层序界面、湖泛面和基准面升降旋回,将松辽盆地朝长地区泉三、四段划分了三级层序1.5个,对应3个基准面升降旋回,四级层序7个,对应14个基准面升降旋回,建立了等时层序地层格架,解决了油层组与层序地层的对应关系问题.在等时层序划分的基础上,确定了扶余油层曲流河、三角洲、湖泊等典型沉积相类型,指出该区沉积来自西南方向物源,储层主要为沿北东向展布、多期叠加的曲流河道砂体.
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